Method of coating and/or impregnating porous substrates, and products obtained thereby

ABSTRACT

This application concerns compositions comprising a mixture of an air-drying dicyclopentenyl acrylate or methacrylate binder and a granular or particulate aggregate material, which may comprise a hydraulic cement, and is adapted to be formed by casting, extruding, or molding in any fashion into any desired shape and air-drying the resulting shaped article, thereby producing an integral, solid article of unitary mass and structure. The dicyclopentenyl (meth)acrylate may be used as an impregnant, polymerizable in situ, for already formed articles of porous nature, e.g., concrete, wood, pressed boards, and pressed powdered metal, such as iron, aluminum, steel, etc., to reduce the permeability at their surfaces and provide hard, continuous, hydrophobic, wear-resistant, and weather-resistant surfaces thereon.

RELATED APPLICATION

This application is a continuation of our copending application U.S.Ser. No. 687,856, filed May 19, 1976, now-abandoned.

DESCRIPTION OF THE INVENTION

In accordance with one aspect of the invention, dicyclopentenyl acrylateor methacrylate or a mixture thereof is used as a hard and hydrophobicbinder material in various particulate aggregate systems, and inaccordance with another aspect is used to impregnate porous material toprovide a hardened, hydrophobic, abrasion-resistant, andimpact-resistant surface on all sorts of materials, especially on formedarticles or formations whether naturally occurring or artificiallyproduced.

In the description hereinafter, the abbreviation DCP(M)A is intended asa generic term to represent one or the other, or a mixture thereof, ofesters of the following formula: ##STR1## wherein R is H or CH₃. The(meth)acryloxy substituent may be on either the 5 or 6 position, thecommercial product being a mixture of the two isomers. The respectiveacrylate or methacrylate of the formula above may also be called:

3a,4,5,6,7,7a-hexahydro-4,7-methanoindenyl acrylate-5 (or 6) ormethacrylate-5 (or 6).

The expression DCP(M)A will be used hereinafter as a generic definitionof either of these monomers or a mixture thereof.

These monomers have low toxicity, low volatility, high flash point, andlow shrinkage on polymerization using an air-drier. All of thesequalities contribute to the effectiveness of DCP(M)A in polymerconcretes (PC) and to the improved qualities of the products obtained ascompared to PC made with such common volatile monomers as methylmethacrylate, styrene, etc. The low shrinkage in the cured products fromDCP(M)A is particularly outstanding and advantageous.

By the term "drier" herein is meant a siccative, that is, a member of agroup of oxidizing substances which, when added to varnishes, paints,etc., hasten the drying or curing. Such substances include thepolyvalent metal salts of inorganic acids or lower aliphatic acids suchas the chloride, nitrate, borate, sulfate, acetate, acetylacetonate, andpropionate when water-solubility is desired, and of higher, aliphaticacids, such as the butyrate, pentanoate, hexoate, and especially thesalts of higher aliphatic acids having from 8 to 30 carbon atoms or ofnaphthenic acids when solubility in organic systems is desired. Theoxides of such metals are also useful. Generally, the most useful driersfor the DCP(M)A of the present invention are salts of naphthenic acidsor of (C₈ to C₃₀) aliphatic acids. Examples of the polyvalent metalinclude calcium, copper^(II), zinc^(II), manganese^(II),manganese^(III), lead^(II), cobalt^(II), cobalt^(III), iron^(III),vanadium^(II), vanadium^(III), and zirconium^(IV). Examples of the acidcomponent or anion of the drier salt is that of acetic acid, propionicacid, butyric acid, acetylacetic acid, naphthenic acids, resinic acids,(that is, rosin acids), tall oil fatty acids, linseed oil fatty acids,2-ethylhexoic acid, lauric acid, palmitic acid, myristic acid, stearicacid, oleic acid, linoleic acid, linolenic acid, behenic acid, ceroticacid, montanic acid, and abietic acid. The driers mentioned in"Encyclopedia of Chemical Technology", Kirk-Othmer, Volume 5, pages195-205, published by Interscience Encyclopedia, Inc., N.Y., 1950, maybe employed. Frequently, mixtures thereof are used. Preferred driersalts are those of cobalt and manganese such as cobalt octoate, cobaltnaphthenate and manganese octoate and naphthenate.

Aromatic amines may be used in small amounts with the drier andgenerally accelerate the action of the drier. For example, aniline,N,N-dimethylaniline, N,N-diethylaniline, toluidine,N,N-di(hydroxyethyl)toluidine, may be added for this purpose in anamount of 0.1 to 2% by weight of the DCP(M)A.

The granular or particulate material that is mixed with the DCP(M)A canbe any material whether capable of curing or not. Examples of inertmaterials are pebbles, sand, or other so-called aggregate materials usedin the making of concrete. The sand that may be used may be of anyquality or of any size, preferably having a diameter of about 1 mm. orless. Graded sand of medium particle size such as "Ottawa" sand and"Best" sand or a mixture of the two may be used to better advantage.Ottawa sand is a silica sand of the type referred to as "round". Bestsand is of the type known as "sharp". In both cases, fines will havebeen removed. In general, however, the sieve size of the sand may varyover a fairly wide range. In lieu of or in addition to sand, it ispossible to use ground glass, emery powder, ground slag, fine gravel,trap rock and similar aggregates.

It is often advantageous to incorporate in the mixture, with or withoutsand, a minor fraction of clay and/or of a hydraulic cement; if so, theclay may take the form of kaolin, china clay, porcelain clay, fire clay,pipe clay, Bentonite, and, in fact, almost any of the known types ofclay. Of course, other materials of pebble nature may be employedincluding broken clay products, marble chips, crushed stone, and othertypical aggregate materials used in the making of terrazzo floors orwalls. The hydraulic cement that may be employed includes Portlandcements of the various types, the white cements, the natural cements,puzzolanic cements, cements derived from industrial slags and "fly ash",aluminous cements, and, in general, all of the commercially availablehydraulic cements. Also included are hydraulic limes and similarmaterials of kinds well known to those skilled in the art.

If desired, a mixture of relatively small-sized particles, such assands, may be employed with large-sized aggregate, such as pebbles,crushed stone, marble chips and the like in various proportions.Preferably mixed aggregates of graded sizes are used to minimize voidvolume, especially to achieve void volumes of less than 0.37, optimallyless than 0.3 to thereby reduce the amount of monomeric DCP(M)A with orwithout other non-volatile monomer to minimize the amount of monomerrequired to fill the voids and thereby minimize the overallpolymerization shrinkage and cost of the monomer component. The mixingof different-sized aggregates to accomplish this low void volumefraction can be performed as described in Encyclopedia of ChemicalTechnology, Kirk-Othmer, Volume 3, pages 466-478, Interscience, 1949.When the DCP(M)A is used as the binder for such inert material, (underanhydrous conditions, any hydraulic cement is properly designated asinert), the proportion of DCP(M)A employed may vary widely dependingupon the porosity and surface area of the aggregate to be boundtogether. For example, the amount of DCP(M)A may be from about 2% byweight to 40% by weight or more of the total weight of hydraulic cementand other aggregate materials to be used in the compositions. In thisregard, the clay and/or hydraulic cement under anhydrous conditions maybe viewed as an "ultrafine" particle sized aggregate component tofurther decrease void volume. The resulting composition can be shapedinto any form desired. The addition of a drier or siccative in smallamounts can be made to the mixture before molding. Alternatively, themolded product can be coated or impregnated with the drier. Theproportion of drier added to composition before molding may be fromabout 0.0005 weight percent up to 2 weight percent based on the weightof the DCP(M)A.

The drier may be kept in a separate package and shipped separately tothe site of operations where the composition of the present invention isto be molded or where a porous product is to be impregnated by theDCP(M)A. The drier, if of rapid-acting type, is preferably mixed intothe DCP(M)A/aggregate mixture shortly before the casting or molding ofthe mixture in the form desired.

The composition may be colored by the choice of a colored aggregate orby including within the aggregate or within the composition a suitableamount of pigment or dye dissolved in the DCP(M)A. The amount of suchpigmentatious or filler material (other than colored sand, aggregate,clay, or the like) may vary from about 1% to 20% by weight of thecomposition.

The formation of the composition by molding may be accomplished in anydesired way. For example, the mixture comprising the DCP(M)A, drier, andaggregate may be poured into suitable molds as in the casting ofconcrete or in the casting of cements that may later be used as wall orceiling tiles or panels. When using it for this purpose, the mixture ofDCP(M)A and aggregate may be so proportioned as to provide a trowellablecomposition. If additional viscosity is needed in such compositions tofacilitate trowelling or other forming actions, a thickening agent orrheological control agent may be included. In general, any moderate tohigh molecular weight resin soluble in the DCP(M)A is useful as arheological control agent. An example of such agent that is quitecompatible and useful with DCP(M)A are the polydicyclopentadienes,commercially available under the registered trademark PICCODIENE®resins. Besides the dicyclopentadiene oligomers mentioned, other viscousoligomers such as of polybutadiene may be employed.

Besides trowelling and/or casting such compositions, they may be formedby extrusion into rods, bars, or sheets of any suitable cross-section.

The formation may be accomplished at room temperature or at highertemperatures if desired. In any event, the composition with which thepresent invention is concerned may be completely free of volatilesubstances so that shrinkage that is difficult to control when othercompositions having volatile components are used is avoided.

Choice of a rapid-acting drier to accomplish the oxidation of the bindercomponent consisting of the DCP(M)A and the hydrocarbon resins used asrheological control resins may result in curing to a solid state in arelatively short time such as from 5 to 20 minutes or so. However,curing of the surface may require additional drying time to overcometackiness because of the inhibition of polymerization of the DCP(M)A byfree radical action occurring at the air/surface interface. This initialtackiness may be overcome more rapidly by coating of the surface shortlyafter formation of the composition with a free radical initiatorcontained in a suitable immiscible liquid that will exclude air from thesurface after application thereof thereto.

The compositions described hereinabove are extremely hard when cured.When it is desired to render such compositions more flexible, theDCP(M)A may be used with auxiliary acrylic and/or vinyl ester bindermaterials which can reduce the hardness and impart a more flexible orresilient character to the final composition. Such other acrylic estermonomers include (C₁₂ -C₃₀)-alkyl or (C₁₂ -C₃₀)-alkenyl acrylates ormethacrylates such as lauryl acrylate, myristyl acrylate, palmitylacrylate, oleyl acrylate, linoleyl acrylate, linolenyl acrylate, stearylacrylate; similar improvements in flexibility may be obtained byincluding with the DCP(M)A long chain (C₁₂ -C₃₀) aliphatic acid vinylesters, e.g., vinyl laurate, vinyl oleate, vinyl stearate or di(C₁ -C₈)alkyl esters of maleic acid, fumaric acid, or itaconic acid, e.g., thediethyl, dibutyl, or dihexyl fumarate, maleate, or itaconate. TheDCP(M)A may also be used with small proportions of multifunctional,i.e., polyethylenically unsaturated monomers, such as allyl(meth)acrylate, polyol poly(meth) acrylate, such as ethylene glycoldiacrylate or dimethacrylate, trimethylolpropane triacrylate ortrimethacrylate, etc. All of these monomeric materials have lowvolatility and are polymerizable either by the action of the siccativeor by free radical polymerization to form products having greatertoughness and resistance to water, solvents, acids, and alkali. Theproportion of these auxiliary monomers may be from about 1/2% to 60% byweight of the DCP(M)A component, but preferably not over about 40% byweight of such component.

When using the DCP(M)A as the binder for inert aggregate material inconjunction with cementitious materials, such as hydraulic cements, (thehydraulic cement constituting a portion of the aggregate under anhydrousconditions), the DCP(M)A may be mixed in with the aggregate comprisingthe cement in sufficient proportion to render the anhydrous mixturetrowellable or having adequate viscosity or plasticity to allowformation by extrusion, casting, or molding. The relative proportionsbetween (1) hydraulic cement and (2) other aggregate material incompositions containing both (1) and (2) may be from 1:100 to 10:1, andis preferably from 1:20 to 3:1.

On the other hand, a small amount of water may be emulsified into themixture using an emulsifying agent if desired. In this instance, thesetting of the cementitious component may depend to some extent upon thecontent of moisture in the mixture as it is formed and/or permeabilityof the formed product to a moist ambient atmosphere although hydraulicaction in setting the compositions of the invention is not vital. Asstated previously, color may be imparted by use of pigment or a coloredcomponent of the aggregate, such as colored marble chips, coloredfractured glass marbles, and the like. Alternatively, a dye for theDCP(M)A may be used or the clay or cement component of the aggregate maybe chosen to contribute to the color of the system.

The DCP(M)A as a binder for cementitious material containing hydrauliccement with or without other aggregate in the form of sand, pebbles, andthe like, may be used in the making of all sorts of formed articles,such as concrete, basements, terrazzo floors, wall and ceiling panels,pavements for roads and bridges, ship floors or decks, and also coatingsfor steel tanks. An example of the use of a composition containing theDCP(M)A binder and a hydraulic cement without aggregate is in thepreparation of mortars or grouts to bind stones, cinder blocks, concreteblocks, bricks, and the like, to form floors, walls, etc. In all suchstructures, the cured product is resistant to water, abrasion, andcorrosive media such as acids and alkalies.

The invention also contemplates the impregnation of already formedarticles having a porous surface with DCP(M)A and a drier (which mayalso contain (1) long chain (meth)acrylates, vinyl esters, or dialkylfumarates, maleates, or itaconates to impart softening, toughness, andflexibility and/or (2) multifunctional monomeric materials, e.g., glycoldimethacrylate for additional crosslinking and improved water-,solvent-, acid-, and alkali-resistant properties) to penetrate at leastthe outer pores of the surface of such porous articles to harden thesurface and make it resistant to penetration by such liquids as water,organic solvent materials, acids, alkalies, and other corrosive liquids.Examples of porous-surfaced materials include concrete, stone masonry orbrick walls including the facings of the mortar between the bricks andthe stones, weathered archeological artifacts and wall structures,weathered granite and marble walks and sculptures previously formed andhardened floors, walls, and ceilings, whether formed of plaster,concrete, cement, wood, pressed boards, pressed metals such as thoseformed of iron, aluminum, and steel binders, and the like. Impregnationof the surfaces of such articles with the DCP(M)A and the drier orsiccative results in the impartation of a hardened, relativelyimpermeable surface adapted to resist indentation by impact as well aspenetration by means of moisture and other liquids such as thosementioned above. Such impregnation results in rendering the objectsresistant to the corrosive and degradative effects caused by weatheringand subjection to atmospheric smog (resulting from discharges into theair of industrial and internal combustion waste gases, e.g., oxides ofsulfur, nitrogen, and carbon, from autos, etc.

Depending on the size of pores existing at the surface of the variousarticles to be impregnated, the DCP(M)A-containing liquid impregnatingcomposition may include preservatives, e.g., for woods or other materialimpregnated, pigments, fillers, and other of the materials includingsmall-sized aggregates mentioned in connection with the compositionsdescribed hereinabove.

In the following procedures illustrating the invention, the parts andpercentages are by weight and the temperatures are in Centigrade unlessotherwise stated.

EXAMPLE 1

A polymer concrete (PC) is prepared by mixing 310 parts of 4-8 mesh(U.S. wire screen standard) crushed stone (having an air void volumefraction of 0.52) with 250 parts of 35-100 mesh sand (having an air voidvolume fraction of 0.43). In the resulting mixture having a coarse/fineweight ratio of 55/45, the air void volume fraction is about 0.28. Aworkably fluid composition is obtained by mixing the resulting aggregatewith about 92 parts of a binder having the following composition:

    ______________________________________                                        Component              Parts                                                  ______________________________________                                        DCPMA                  102                                                    Rheology agent*        18                                                     Cobalt naphthenate      4                                                     (6% Co)                                                                       ______________________________________                                         *A polydicyclopentadiene available under the registered trademark             Piccodiene 2215, which has a softening point of 103° C., a specifi     gravity of 1.10, a bromine No. of 39, an iodine No. of 142, an acid No. o     1.0, a saponification No. of 2.0, and a melt viscosity of 1 poise at          213° C., 10 p. at 170° C., and 100 p. at 142° C.    

The resulting mixture is poured into a mold 2 inches deep. The castcomposition is substantially cured to solid condition in about 6 hoursat room temperature. Essentially complete cure, with tackfree surface,occurs overnight. A tough, water-impermeable casting is obtained.Specific gravity is 2.10 and compressive strength is 5400 psi. (onemonth cure). The concrete exhibits a weight increase of only 1/4% afterthree weeks immersion in water.

A concrete prepared with the same aggregate mixture but using 172 partsof Portland Cement and 86 parts of water (the minimum needed to yield aworkably fluid concrete) as the binder has a specific gravity of 2.30and a compressive strength of 4400 psi. (one month cure). This resultingconcrete exhibits an increase of about 6% by weight after three weeksimmersion in water.

EXAMPLE 2

Example 1 is repeated but using the following binder composition:

    ______________________________________                                        Component              Parts                                                  ______________________________________                                        DCPMA                  78                                                     di(n-butyl)fumarate    24                                                     Rheology agent of      18                                                     Example 1                                                                     Cobalt naphthenate      4                                                     (6% Co)                                                                       ______________________________________                                    

The mixture is cast as in Example 1. It cures to a substantially solidcondition in about 6 hours. Essentially complete cure, with tackfreesurface occurs overnight. A tough, water-impermeable casting isobtained. Specific gravity is 2.22 and compressive strength is 5400 psi.

EXAMPLE 3

Example 1 is repeated but using the following binder composition:

    ______________________________________                                        Component              Parts                                                  ______________________________________                                        DCPMA                  85                                                     Rheology agent of      15                                                     Example 1                                                                     Dimethyl aniline       1                                                      Cobalt naphthenate     1                                                      (6% Co)                                                                       Methacrylic acid       0.5                                                    ______________________________________                                    

The mixture is cast as in Example 1. It cures to a substantially solidcondition in about one hour at room temperature. Essentially completecure, with tackfree surface, occurs overnight. A tough,water-impermeable casting is obtained. Specific gravity is 2.11.

EXAMPLE 4

A polymer-containing concrete is prepared by mixing 10 parts of Whitecement and 310 parts of 4-8 mesh (U.S. wire screen standard) crushedstone (having an air void volume fraction of 0.52) with 250 parts of35-100 mesh sand (having an air void volume fraction of 0.43). In theresulting mixture having a coarse/fine weight ratio of 55/45, the airvoid volume fraction is about 0.28. A workably fluid composition isobtained by mixing the resulting aggregate with about 103 parts of abinder having the following composition:

    ______________________________________                                        Component              Parts                                                  ______________________________________                                        DCPMA                  85                                                     Rheology agent of      15                                                     Example 1                                                                     Dimethyl aniline       1                                                      Cobalt naphthenate     1                                                      (6% Co)                                                                       Methacrylic acid       0.5                                                    ______________________________________                                    

The resulting mixture is poured into a mold 2 inches deep. The castcomposition is substantially cured to solid condition in about an hourat room temperature. Essentially complete cure, with tackfree surface,occurs overnight. A tough, water-impermeable casting is obtained.

EXAMPLE 5

A cementitious but essentially anhydrous mortar is prepared from amixture of the sand of Example 1 and Portland cement having a voidvolume fraction of 0.6 and a particle size range of 1 to 100 microns ina (bulk) volume ratio of 2:1 (weight ratio about 2.64:1) by adding tothis sand/cement mixture having a void volume fraction of 0.35, justbefore use, the following binder composition:

    ______________________________________                                        Material               Parts                                                  ______________________________________                                        DCPMA                  100                                                    Dimethyl aniline       1                                                      Cobalt naphthenate     1                                                      (6% Co)                                                                       Methacrylic acid       0.5                                                    Total                  102.5                                                  ______________________________________                                    

The amount of binder incorporated is sufficient to render the mixturetrowellable, being about 25 parts binder per 100 parts by weight ofsand/cement mixture. When applied in a half-inch thickness to a glasstest plate, the mortar cures in a few hours to hard, adherent,water-resistant material. Similar results are obtained when the DCPMA ispartially or completely replaced with DCPA.

EXAMPLE 6

A concrete slab is impregnated with DCPMA containing dissolved therein0.06% cobalt as the naphthenate by applying a liberal coating thereof tothe surface of the slab and allowing it to soak in for six hours,resulting in a weight gain of about 3% after wiping off the excessDCPMA. Air-curing is then allowed to occur, yielding after about a day ahydrophobic water-impermeable surface having good water-repellency. Thisprocedure is particularly useful for treatment of pavements on bridgedecks and on ship decks.

For this purpose, it has heretofore been suggested to impregnate thepavement or floor with a volatile monomer, such as methyl methacrylate,containing a free radical polymerization initiator. Such systems havethe disadvantages of high volatility and low flash point, which makeworking with these systems dangerous to the personnel handling thesystems and the impregnant has a short pot life.

The impregnating system of the present invention comprises non-volatileimpregnant DCP(M)A, with or without up to 35% by weight of anotherrelatively non-volatile monomer, 0.0005 to 2% by weight drier, and withor without 0.1 to 2% by weight of a volatile stabilizer, e.g., aketoneoxime or an aldehyde-oxime which inhibits the oxidative action ofthe drier till the stabilizer is volatilized. The percentages are basedon the weight of the impregnating composition. This composition haspractical pot life and contains a relatively small amount of volatilematerial. Specific examples of volatile oximes are methyl ethylketone-oxime, methyl butyl ketone-oxime, 5-methyl-3-heptanone-oxime,cyclohexanoneoxime and butyraldehyde-oxime.

We claim:
 1. A method of providing a porous-surfaced formation with ahardened, abrasion-resistant, relatively impermeable surface adapted toresist indentation by impact as well as penetration by moisture andother liquids, thereby rendering such porous-surfaced formationresistant to weathering and atmospheric smog which comprisesimpregnating the porous surface of the formation with a solution of ametal-containing drier in a liquid mixture of(A) at least one ofdicyclopentenyl acrylate and dicyclopentenyl methacrylate with (B) about0.5% to 60% by weight, based on the weight of (A), of another relativelynon-volatile monomer selected from the group consisting of C₁₂ -C₃₀alkyl and C₁₂ -C₃₀ alkenyl acrylates and methacrylates,the amount ofdrier in the solution being from 0.0005 to 2 weight percent based on theweight of (A), and allowing the applied solution to oxidatively cure inthe presence of air at ambient conditions.
 2. A method according toclaim 1 in which the formation is a concrete floor, pavement, or deck ona ship or bridge, or is a weathered archeological artifact, sculpture,or formation.
 3. A method according to claim 1 in which the drier is anoxide, complex or salt of a polyvalent metal selected from calcium,copper, zinc, manganese, lead, cobalt, iron, and zirconium.
 4. A methodaccording to claim 2 in which the drier contains cobalt^(II).
 5. Amethod according to claim 2 in which the drier contains cobaltnaphthenate.
 6. A method according to claim 1 in which the solutionapplied also contains 0.1 to 2% by weight of a volatile ketone-oxime oraldehyde-oxime stabilizer.
 7. A product of the process of claim
 1. 8. Aproduct of the process of claim
 2. 9. A product of the process of claim3.